This study aims to define clinical, radiographic and pathologic characteristics of early breast cancer and its precursors, to determine the diagnostic criteria and patterns of criteria for detection and diagnosis of early breast cancer and to determine high-risk groups of patients, using discriminant analysis procedures on data carefully collected and edited over the past 13 years at Emory University. We will calibrate discriminant function classifications and provide estimates of probability of breast cancer in each risk hierarchy (patient risk). The scheme will then be applied to populations independent of those used to define the discriminant functions to evaluate its effectiveness and usefulness. The data base will be up-dated and augmented in preparation of analysis for study of treatment planning, prognosis and natural history of breast cancer. BIBLIOGRAPHIC REFERENCES: Egan, R. L.: Evolution of the team approach in breast cancer. CANCER 36:5:1815-1822, November, 1975. Egan, R.L.: Breast biopsy priority: Cancer versus benign preoperative masses. CANCER 35:3:612-617, 1975.